• Proceedings of the Korean Geotechical Society Conference
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• 한국지반공학회 1993년도 봄 학술회 논문집
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• pp.41-48
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• 1993

The 2nd phase of Seoul Subway, Lines 5,6,7 and 8, is in progress. To reduce the surface traffic congestion during construction the greater part of the system has been engineered by bored tunnelling. The current tunnelling methodology is based on the New Austrian Tunnelling Method. Serveral collapses have been reported to date. Most of the collapses took place in the area forwed with soft ground. The modes and causes of the collapses were progressive failures in the unsupported surface and sliding failures due to the unfavourable joint direction. The major causes turned out to be the weakness of ground and the sudden influx of ground water from the surface. Some measures to prevent the failures are also presented. To ensure the safe tunnelling ghrough the soft ground the unsupported excavation area has to be minimized and closed as early as possible. Additional support measures such as supporting core, sealing shotcrete, forepoling, spread footing, face rock bolting and grouting should be employed as well depend on ground conditions.

• Structural Engineering and Mechanics
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• 제60권5호
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• pp.829-849
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• 2016

In this paper, experimental as well as numerical analysis of Glass Fiber Reinforced Polymer (GFRP) laminated composite has been presented under ballistic impact with varying projectile nose shapes (conical, ogival and spherical) and incidence velocities. The experimental impact tests on GFRP composite plate reinforced with woven glass fiber ($0^{\circ}/90^{\circ}$)s are performed by using pneumatic gun. A three dimensional finite element model is developed in AUTODYN hydro code to validate the experimental results and to study the ballistic perforation characteristic of the target with different parametric variations. The influence of projectile nose shapes, plate thickness and incidence velocity on the variation of residual velocity, ballistic limit, contact force-time histories, energy absorption, damage pattern and damage area in the composite target have been studied. The material characterization of GFRP composite is carried out as required for the progressive damage analysis of composite. The numerical results from the present FE model in terms of residual velocity, absorbed energy, damage pattern and damage area are having close agreement with the results from the experimental impact tests.

• 한국해양학회지
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• 제22권3호
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• pp.119-129
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• 1987

Sediments in the cores from the KONOD-1 area consist mainly of authigenic smectite and clinoptilolite, and terrigenous minerals of illite, chlorite, kaolinite, quartz, and plagioclase. The authigenic minerals become dominant over the terrigenous minerals with increasing depth. Clinoptilolite occurs at the deeper core depth because its formation is slower than that of smectite. The vertical distribution of minerals indicates that the eolian influence, probably in the late Oligocene, diluted the abundance if smectite in near-surface sediments. This vertical distribution pattern may also have been affected by progressive dissolution of authigenic minerals in the near surface sediments.

• The Korean Journal of Physiology
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• 제5권1호
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• pp.1-9
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• 1971

Body volume, density and %fat were calculated by means of formulas using body height, weight, and surface area in 1,732 children aged between 6 and 12 years. Skinfold thicknesses on back, arm, waist and abdomen were measured by means of a Lange caliper. The course of increase in body volume was identical to those of body height, weight, relative weight and surface area. Curves of boys and girls showed a cross at the age of between 10 and 11 years. Body density of boys increased with the age and it decreased in girls. Total body fat showed a progressive decrease from the age of 6 in boys. In girls body fat increased progressively with the age. Skinfold thickness increased both in boys and girls with the age. At the same age skinfold thicknesses on all sites were greater in girls than boys.

• Journal of Ecology and Environment
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• 제44권3호
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• pp.126-142
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• 2020

Background: Most of the Pinus densiflora forests, occupying the largest area, have been restored in South Korea since the 1970s. As young pioneer forests, the succession process is under way. Since the forests are distributed nationwide and are vulnerable to disturbances, the process may differ depending on the geography and/or site conditions. Therefore, we reviewed the direction, the seral communities, and the late-successional species of progressive and disturbance-driven succession nationwide in the cool-temperate zone through meta-analysis and empirical observations. Main text: As a result of a meta-analysis of the direct succession and vertical structure, we found that the P. densiflora forest is in a directionally progressive succession, changing to the broadleaved forest after forming a mixed forest with its overwhelming successor, Quercus species (particularly Q. mongolica and Q. serrata). In dry stands in a relative sense, the Quercus species was favored occupying over 80% of the abundance of the succeeding species. Therefore, in dry stands, it is presumed that Quercus-dominated stage would last for a long time due to the current dominance and long life span, and eventually, it settles as Quercus-broadleaved forest with a site change. Contrary to this, it is presumed that in mesic stands where Quercus species do not occur or have low abundance, the late-successional broadleaved species settle early to form a co-dominant forest with multiple species. Due to geographical limits, the species composition of the two late-successional forests is different. Disturbances such as insect pests and fire retrogressed vulnerable P. densiflora forest for a while. However, it was mostly restored to the Quercus forest and is expected to be incorporated in the pathway of the dry stand. Conclusions: We revealed the succession process of P. densiflora forests according to geography and moisture and found that stand moisture had a decisive effect on the species and abundance of the successor. Although the P. densiflora forest is undergoing structural changes, the forest is still young; so within a few decades, physiognomy is not likely to change. Therefore, the decrease in the forest area may be due to other causes such as disturbances and forest conversion rather than due to succession.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제33권4호
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• pp.368-372
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• 2011

Progressive transformation of germinal centers (PTGC) is mostly a disease of young adults and it presents as unexplained, asymptomatic, localized or generalized lymphadenopathy that is usually persistent or recurrent over a period of many years. PTGCs are larger than regular germinal centers and they contain a variable proportion of small mantle zone lymphocytes and so they become progressively transformed and they may result in the loss of clear demarcation between them and the mantle zone. PTGC may resemble the nodules of nodular lymphocyte predominant Hodgkin's disease (NLPHD) and it may be mistaken for NLPHD. Histological and immunohistochemical studies are helpful in differentiating these diseases. Because of the relatively frequent recurrences of PTGC, follow-up and repeat biopsy are indicated. Although PTGC is not considered to be a premalignant condition, PTGC may occur prior to, concurrent with or following NLPHD. This emphasizes the need for ongoing follow-up and repeat biopsy. Although PTGC is reported in 3.5% to 10% of the cases of chronic nonspecific lymphadenopathy, oral & maxillofacial surgeons are not widely aware of this condition and its clinical implications. Herein, we present a case of PTGC. A 24-year-old male without any history of immunodeficiency or autoimmune disease was admitted to the Department of Oral & Maxillofacial surgery at Ulsan University Hospital for evaluation of a right submandibular swelling. He had another mass on the right thigh that was noticed about 1 year ago. The submandibular lesion was completely resected and biopsied. The histological findings and immunohistochemical stains (CD3, CD15, CD20, CD30, CD57, BCL-2, EMA) were consistent with PTGC. He was followed up without any other complaints for 9 months.

• Korean Journal of Applied Biomechanics
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• 제13권3호
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• pp.241-252
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• 2003

The purpose of this study was to evaluate performance characteristics in the success of team attack during volleyball game. Three dimensional analysis was performed with games of business teams. Analyzed variables were followed by the movement distance of a setter when A-quick was occurred, the position during the spike, the possibility area during the attack, the right and left distance of the assistance attacker, the distance between attacker and blocker, and the distance between blockers each others. 1. It is recommended that the movement distance of the setter be decreased in order to make stable set condition. 2. In order to make one person blocking, the formation was to be consisted of the right and left formation which was associated with the progressive attack performance of the assistance attacker. 3. It is useful to widen attack area. Also it is necessary to improve the enhancement of passing the ball against the blocking of an opponent player. Finally, it is necessary to develop kinematic variables to evaluate performance characteristics of players. Further study may consider the best defense position against the attack of the opponent player.

• Korean Journal of Ecology and Environment
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• 제38권spc호
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• pp.67-75
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• 2005

The objectives of this study were to understand the runoff characteristics of the non-point sources originating from impervious surfaces and to assess their effect on the aquatic environment in the urban areas. The concentration of pollutants (SS, BOD, COD and T-P) except for T-N showed the highest value in runoff from road, and event mean concentration (EMC) also showed high value from road. The pollutants discharged from road showed a higher concentration in the beginning stage (0 ${\sim}$ 30%) of progressive percentage of rainfall. The contribution percentages of non-point sources by load were 44.9% for SS, 11.2% for BOD, 21.4% for COD, 11.4% for T-N and 8.1% for T-P in the total load of pollutant discharged through sewer. From our results, the road was a significant potential source that deteriorated water quality of the streams and lakes in the vicinity of the urban area during the rain period. Therefore, counter plan is required to reduce pollutant concentration on the road from non-point sources in the urban area. Also, since pollutant concentration in the beginning stage of rainfall was quite high, road cleaning seems to be one of the very useful methods to prevent inflowing of pollutants to the aquatic environment.

• Journal of Chest Surgery
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• 제31권4호
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• pp.422-426
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• 1998

Progressive dysphagia in a 53 year old man was caused by a giant polypoid tumor in the lower intrathoracic esophagus. Radical transthoracic esophagectomy and esophagogastrostomy were carried out. Microscopic examination of the tumor revealed a true carcinosarcoma, composed of a mixture of basaloid squamous cell carcinoma and chondrosarcoma with multiple cartilagenous productions. Carcinoma metastases were found in the subcarinal and perigastric lymph nodes. Immunohistochemically, squamous area displayed strong positive to cytokeratin, and basaloid area showed positive immunoreaction to high molecular weight cytokeratin (34${\beta}$E12). Spindle cell sarcoma reacted to vimentin and smooth muscle actin. Chondrosarcomatous area reacted to vimentin and S-100 protein. He received postoperative chemotherpy and radiotherapy. He has been free of disease for 11 months.

• Journal of the Korean Regional Science Association
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• 제8권1호
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• pp.31-50
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• 1992

The aim of this paper is to define major factors influencing land development of each of major uses (residential, commercial, industrial) in the process of rapid urban expansion. The main hypothesis of this study is that land use changing patterns are directed by supply side of land managed to public policies rather than demand side. The graphic analysis is applied to relationships between urban growth and land development process of each use and between land development project managed to public policies and land development process. Public and land development projects and zonning protection seem to be major roles of land supply and main determinants of urban spatial structure. Location factors for land development of each uses are selected in 23 variables. Factor analysis is applied to test correlation between variables in 1971 and 1981. Factor structure between two years is similar, but progressive processing of functional separation is derived such as intensive land use is grouped, different location between residential and industrial use is deep. Dependent variables are standardized to logarithm of land development of each use per unit vacant land in two periods, between 1971 and 1980 year and between 1981 year. Correlation analysis between 6 dependent variables and 23 location factors in each years are applied. Major factors of each use are selected in criteria such as high correlation with dependent variables, low correlation between independent variables and common application in two periods. As the result, major factors for residential land development are Land Readjustment Project (LRP), percent of total zoned area in residential zone, residential floor space density per available area, percent of total area in industrial use; for commercial development is distance to CBD, percent of total area in commercial use, residential floor space density per available area in each year, and volumn rate of industrial use; for industrial use is percent of total area of industrial use is percent of total area of industrial use, Industrial Estate Project (IES), LRP, and distance from CBD. Land development pattern of each use between two periods are slightly different. So 6 equation is derived from appling backward method of regession. Adjusted multiple R squares of all is more than 0.5 and those equation is statistically significant and valuable to assist urban land use forecasting.